Manufacture of artificial filaments



i atented Feb. 12, 1935 MANUFACTURE OF ARTIFICIAL FILAMENTS Rudolf Etzkorn, Oberbruch, Germany, assig'nor to North American Rayon Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application September 11, 1931, Serial No. 562,426. In Germany September 16,

2 Claims.

My present invention has to do with a control of the spinning or take-up speed in the production of .artificial filaments.

One object of my invention is to provide a novel 5 method for economically increasing the take-up speed of extruded filaments.

Another object is to provide a method for controlling the radius of the take-up roller.

Other objects will become apparent from a pcrusal of the following specification.

In the manufacture of artificial filaments where a liquid coagulating or precipitating medium is employed, when the speed of the issuance of the filaments increases there is a corresponding increase in the amount of the bath liquid carried away by the moving filaments. Attempts have been made to control this removal of liquid by mechanical means. For example, in the copending Glanzstoff application, Serial Number 452,700 filed May 15, 1930, a round thread guide is situated near the surface of the bath and is of such a size that the filaments practically do not touch its sides in passing therethrough.

Some type of control is absolutely necessary when the take-up speed of the filaments is high, especially when it reaches meters per minute, and above. Sometimes, when no control is used, the bath is carried off at a high rate of speed and soon becomes too low for use. Then too, the centrifugal force exerted by the take-up roller throws the bath around the machine. If water alone is used this is inconvenient. If a chemical bath is used this is dangerous.

However, it has been found that the mechanical controls so far presented have not entirely cured the defects mentioned since some of the bath liquid tends to sputter ofi from the take-up roll. I have discovered that this spraying of liquid may be eliminated if the centrifugal acceleration on the surface of these rollers is kept below a certain level. I have determined this to be a level of 2500 centimeters per second squared. In order to keep the centrifugal acceleration at high take-up speeds below this rate, the diameter or radius of the take-up rollers is measured with reference to the surface speed to be employed. That is, rotating rollers are used, which must not fall below a certain diameter length at a corresponding speed. I have found that the radius r of the rotating rollers for every speed V may be determined in centimeters through the use of the equation:

The following graphic chart may also be used:

RADIUS IN CM lOO TAKE UP SPEED M /MIN claim is:

1. In a process of the class described, the step of collecting spun filaments or threads at a speed of at least 100 meters a minute without appreciable splashing of liquids, which includes the step of controlling the diameter of the take-up roller so that the linear acceleration of its surface does not exceed 2500 cm/sec.

2. In the manufacture of artificial filaments by the wet-spinning process, at spinning speeds of approximately 100 meters per minute, the step of practically eliminating the splashing of bath liquids comprising controlling the diameter of the take-up roller so that-the surface acceleration of the same is not greater than 2500 RUDOLF ETZKORN. 

